Sewing machine



F. A. REECE.

SEWING MACHINE.

APPLICATION FILED'JUNE 14. 1919.

1,424,,85 1 n Patented Aug; 8, 11.922-

2 SHEETS-SHEET' llnven'for. FrunKiin A.Reece F. A. REECE.

SEWING MACHINE.

APPLICATION FILED JUNE 14. 1919.

1 A24}, 85 1 o Patented Aug. 8, 1922.

2 SHEETSSHEET 2- FUJMQQ 40 BnvenVor.

Em A. eece sates Fammm' A. REESE, or CHESTNUT HILL, MASSACHUSETTS; ASSIGNOR 'ro THE amen BUTTON HOLE MACHINE COMPANY, or BOSTON, massacnosnr'rs, A

' QOBPORATION OF MAINE.

Application filed .Tune 14,

To all whom it may concern.

Be it known that I, FRANKLIN A. Rnncn, a citizen of the United States, residin at Chestnut Hill, county of Middlesex, tate of Massachusetts, have invented an Improve ment in Sewing Machines, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts.

.'This invention relates to sewing machines of that type in which the under thread mechanism is in the form of a stationary bobbin case or shuttle adapted to receive a bobbin and a rotary hook constructed to take a loop of needle thread and cast it about the shuttle case thereby to interlock the needle thread with the shuttle thread.

One of the objects of the invention is to provide a novel construction wherein the thread from the bobbin will be delivered to the work through a guide-eye formed in the shuttle case that is situated directly beneath the line of stitching so that the portion of the under thread extending from the shuttle case to the work is in a substantially vertical plane which is parallel with the lineof feed and extends through the stitching point.

Other objects are to provide further improvements relating to sewing machines of this type, all as will be more fully hereinafter set forth.

While my invention might be embodied in various machines in which the under thread mechanism is in the form of a stationary bobbin and rotary hook, I have herein chosen to illustrate it as it would be applied to a buttonhole sewing machine such as is'shown in my co-pending application Se. No. 280,704, filed March 5, 1919. Inasmuch, however, as my invention relates simply to the under thread mechanism, I have not deemed it necessary to show a complete buttonhole sewing machine.

In the drawings, Fig. 1 is a front view of the under thread mechanism of a buttonhole sewing machine such as illustrated in my co-pending application and having my present improvements applied thereto;-

Fig. 2 is a top plan View of Fig. 1;

Fig. 3 is a side View;

Fig. 4 is an enlarged front view of the bobbin-case and the rotary hook;

Specification of Letters Patent.

SEWING- MACHINE. I

Patented Ang.8,1t922.

1919. Serial No. 304,223.

through a buttonhole showing the manner lIlWhlCh my improvements assist in laying the purl -evenly each side of the buttonhole s it;

Fig. 8 is a bottom side View of a portion of a buttonhole made on my machine.

1 indicates part of the frame of the sewing machine which supports the under thread mechanism and which is situated beneath the bed plate indicated by the dotted line 2, Fig. 1. 3 indicates the needle bar which carries the upper eye-pointed needle 4, said needle being situated above the Work and controlling the upper or needle thread.

26 indicates the throat-plate which is carried by the frame 1 and has the opening 25 therein through which the needle 4 passes when it makes its penetrating thrust. In the construction herein shown, this throat-- plate is shown as having a slit 27 .therein to receive the knife which cuts the buttonhole.

The under thread mechanism is of the familiar type which comprises a stationary bobbin case 5 in which is received a bobbin holder 6 in which the bobbin is placed, said bobbin holder being retained on an axial stud 7extending from the bobbin case and being locked thereon by means of the usual spring-pressed locking lever 8. The rotary hook which takes the loop of needle thread and casts the same about the bobbin case is indicated generally by 9, said hook being carried by a short shaft 10 which is journaled in bearings 11 formed on the frame 1 and has fast thereon a gear 12 that meshes with a gear 13 on a driving shaft 14. The gears 12, 13 are two-to-one gears so that the hook will make two rotations to each rotation of the shaft 14. The shaft 14 is so connected to the mechanism which reciprocates the needle 3 that the shaft 14 will rotate once for each reciprocation of the needle, all as shown in my said co-pending application. The hook, therefore, rot-ates twice for each reciprocation of the needle, and the object of this construction is to give the hook a sufliciently rapid turning movement to ca the loop of needle thread about the bobbincase and pull up the loop before the needle again enetrates the. ork. he hook memher 9 is provided with the usual finger 15 which is constructed so that as it passes the upper center, it will engage the loop 16 of needle thread, as shown in Fig. 4, and the complete rotation of the hook 9 will operate to cast this loop about the bobbin case 5, as usual in sewing machines of this type.

type.

' a vertical direction and in a vertical plane extending parallel to the line of feed and Oneobject of my present invention is to provide a novel means for controlling the under or bobbin thread 20 so that it will be delivered from the bobbin case to the work in passing through the line of stitching. In this type of sewing machine the bobbin thread is led from the bobbin through a ten-. sion device 21 and is delivered under a guidefinger 22, as shown inFig. 4, said guide finger being situated at one side of the line of stitching which is indicated by .the vertical line 23. In my improvements, I have provided the bobbin case with a guide aperture 24: situatedat the top center thereof and directly underneath the line of stitchingIand the bobbin thread extends from the guidefinger 22 through this guide aperture 24 and thence to the work. This guide aperture 24 is directly beneath the line of stitching so that the portion of the bobbin'thread which passes from said guide-eye 24 to the aperture 25 in the throat-plate 26 is in a vertical plane extending in the direction of feed.

In operating my machine, I propose to adjust the tension device 21 so that it will apply to the under thread 20 a much heavier tension than is applied to the upper or needle thread. When the tensions of the two threads have this relative adjustment the purl or point of interlock between the upper and under threads will be drawn on the underside of the work. This is shown in Figs.

7 and 8. The heavy tension on the under thread 20 will cause it to be laid in a substantially straight line along the edge of the buttonhole slit, while the upper thread 41 will be formed in loops 40 which are interlocked with the under thread 20. This interlocking forms the so-called purl of the buttonhole and will be positioned on the under side of the work close to the buttonhole slit, as seen in Fig. 8. Where the purl is formed in this way, it is, of course, important that the purl on both sides of the buttonhole should be properly spaced with reference to the buttonhole slit and by having the shuttle or bobbin thread delivered to the work in a vertical line from the opening 24 there will be no tendency to pull. the purl out of proper position as would be .the case if the shuttle thread were delivered ,to the work directly from the finger 22 in an inclined direction.

In the operation of casting the loop 16 of needle thread-around the shuttle case,-one leg of the loop will pass between the finger 18 and the shuttle case. The rotary movement of the hook which takes place in the direction of the arrow, Fig. 4,-tends to hold the side 2801 the'notch against the finger 18, as shown in Fig. 2,'and this contact between \the finger and wall 28 of the notch tends to interfere with the free passage of'one leg of the needle loop between said parts, especially when the hook is operating at ahigh speed. I have provided means which acts on the bobbin case just as the needle loop is to be passed around the finger 18.which moves the bobbin case back slightly so as to open a space between said finger and the wall 28 of the notch thereby allowing the loop of, needle thread tofreely pass the finger 18. For this purpose, the bobbin case is provided with a projection 29 which is acted on by a finger 30 carried by a rock-shaft 31, said finger being given a slight downward movement after the loop of needle thread has passed the projection 29 and before it reaches the projection 18. The rock-shaft 31 is carried in a suitable bearing 61 formed on the frame 1 and is provided on its inner end with another arm 32 adapted to engage a cam 33 on the shaft 14,-said rock-shaft 31 being acted on by a spring'34 which holds the arm 32 in contact with the cam 33. When said arm 32 is in engagement with the low portion of the cam 33, as indicated in Fig. 1, the arm 30 w-ill'be separated slightly from the projection 29, thus allowing the loop of needle thread to pass freely between these parts. After the loop of needle thread has passed the projection 29 the high part of the cam 33 will engage the arm 32, depress ing the latter and thereby moving the arm 30 down, such downward movement being sufficient to cause the arm 30 to engage the projection 29 and thus move the bobbin case slightly in a clockwise direction. Such movement is sufficient to separate the projection 18 from the wall 28 of the notch so that the loop of needle thread will pass freely around the projection 18 without being caught thereon. .In this way the mechanism can be operated at an increased speed with out danger of the bobbin thread being caught on any projections on the bobbin cas ing or subjected to any jerky action, such as would result if it had to be drawn around the projection 18 while the latter was in contact with the wall 28 of the notch. This feature of giving the bobbin case a slight backward movement is not herein claimed.

It will be noted that the slit 27 in the th-roati-pilate'which co-operates with the usual cutter for cutting the buttonhole is separate from the sewing hole through which the needle 4 operates and as a result the rear wall of said hole 25 is solid and unbroken.

Where the slit 27 is separate from the opening 25 in the throat-plate, the rear wall of said opening will be unbroken. This is of special advantage where the sewing machine is operating to draw the purl on the under side of the work, as shown in Figs. 7 and 8, because when the work is being fed to the rear or to the right in Fig. 3 and the purl is being drawn over the rear edge of the sewing opening, there will be no tendency for said purl to be carried into the buttonhole slit and thus displace laterally as would occur if the buttonhole slit communicated with the sewing. opening.

In buttonhole sewing machines of the lock stitch type in which the entire mass of under thread is passed through a loop in' the needle thread during the formation of each stitch, the size of the thread mass on the bobbin or in the shuttle is, ofcourse, limited. When a lock stitch sewing machine is operating as above described to form the purl on the under side of the thread, the greater portion of the thread used in makin each stitch will be taken from the upper thread supply, and the under thread will extend along in a substantially straight line, as indicated in Fig.

8. Thethread supplyfor the upper thread can without inconvenience be a relatively large thread mass, such as a large spool, and by thus forming the purl on the under side of the work, a minimum amount of under thread is used in forming each stitch. By

this means the relatively small amount of under thread which is contained in the bobbin will be sufficient to make a much larger number of buttonholes than if the purl were drawn to the top of the work so that a con siderable portion of each stitch came from the bobbin.

I claim:

1. In a two-thread lock-stitch buttonhole sewing machine having a-needle for manipulating the upper thread and a bobbin for the under thread, which bobbin is inserted through a loop of needle thread at each stitch, the combination with said needle and bobbin, of means to interlock the needle thread and bobbin thread and to produce two parallel lines of stitching on opposite sides of the buttonhole and spaced from each other with the point of interlocking constituting the purl on the under side of the Work, and a guide for the bobbin thread as it passes from the bobbin to the work, said guide being situated in a vertical planemidway between said lines of stitching.

2. In a two-thread lock-stitch buttonhole sewing machine having a needle for manipulatin the upper thread and a bobbin for the un er thread, which bobbin is inserted through a loop of needle thread at each stitch, the combination with said needle and bobbin, of means to interlock the needle thread and bobbin thread thereby to form two' parallel lines of stitching on opposite sides of a buttonhole, and means to guide the bobbin thread so that the portion of the thread extending from the guiding means to the work will have the same angular relation to the work during the formation of the stitches on both sides of the buttonhole.

3. In a two-thread lock-stitch buttonhole sewing machine having a needle and a bobbin which is inserted through a loop of needle thread at each stitch, the combination with said needle and bobbin, of a throat plate situated beneath the work and through which the needle operates, meansio cause the needle and bobbin thread to interlock on the side of the work adjacent to the throatplate, and a guide-eye through which the bobbin thread is delivered to the work, said guide-eye being situated directly beneath the slit of the buttonhole whereby the purl on both sides of the buttonhole will be located equidistant from the buttonhole slit.

4. In a two thread lock-stitch buttonhole sewing machine having a needle for manipulating the upper thread and a bobbin for the under thread, which bobbin is inserted through a loop of needle thread at each stitch, the combination with said needle and bobbin, of means to interlock the needle thread and bobbin thread thereby to form two parallel lines of stitching on opposite sides of a buttonhole with the point of interlocking on the under side of the work, and.

means to guide the bobbin thread so that the portion of the thread extending from the guiding means to the work will have the same angular relation to the work during the formation of the stitches on both sides of the buttonhole.

5. In a buttonhole sewing machine, the combination with stitch-forming mechanism to interlock upper and under threads and constructed to form the purl of the buttonhole on the under side of the work, of a throat-plate having a sewing holethrough which the under thread is led and also having a slit to co-operate with a buttonholecutting knife, and means to prevent the purl of the buttonhole from entering said slit as the work is fed toward the slit from the sewing opening.

In testimony whereof, I have signed my FRANKLIN A. REECE. 

